結果

問題 No.2337 Equidistant
ユーザー siganaisiganai
提出日時 2023-06-02 22:25:49
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 909 ms / 4,000 ms
コード長 8,883 bytes
コンパイル時間 3,557 ms
コンパイル使用メモリ 214,216 KB
実行使用メモリ 51,968 KB
最終ジャッジ日時 2024-12-28 19:36:17
合計ジャッジ時間 14,864 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge2
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
5,248 KB
testcase_01 AC 2 ms
5,248 KB
testcase_02 AC 3 ms
5,248 KB
testcase_03 AC 2 ms
5,248 KB
testcase_04 AC 3 ms
5,248 KB
testcase_05 AC 2 ms
5,248 KB
testcase_06 AC 5 ms
5,248 KB
testcase_07 AC 4 ms
5,248 KB
testcase_08 AC 4 ms
5,248 KB
testcase_09 AC 3 ms
5,248 KB
testcase_10 AC 5 ms
5,248 KB
testcase_11 AC 345 ms
27,264 KB
testcase_12 AC 343 ms
27,392 KB
testcase_13 AC 331 ms
27,008 KB
testcase_14 AC 337 ms
27,392 KB
testcase_15 AC 316 ms
27,136 KB
testcase_16 AC 526 ms
27,392 KB
testcase_17 AC 544 ms
27,264 KB
testcase_18 AC 527 ms
27,392 KB
testcase_19 AC 532 ms
27,392 KB
testcase_20 AC 497 ms
27,392 KB
testcase_21 AC 682 ms
51,968 KB
testcase_22 AC 221 ms
27,324 KB
testcase_23 AC 301 ms
27,648 KB
testcase_24 AC 834 ms
45,440 KB
testcase_25 AC 292 ms
27,520 KB
testcase_26 AC 909 ms
45,312 KB
testcase_27 AC 293 ms
27,648 KB
testcase_28 AC 309 ms
27,648 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#line 1 "main.cpp"
//#pragma GCC target("avx")
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#ifdef LOCAL
#include <debug.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
using namespace std;
using ll = long long;
using ld = long double;
using pll = pair<ll, ll>;
using pii = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vpii = vector<pii>;
using vpll = vector<pll>;
using vs = vector<string>;
template<class T> using pq = priority_queue<T, vector<T>, greater<T>>;
#define overload4(_1, _2, _3, _4, name, ...) name
#define overload3(a,b,c,name,...) name
#define rep1(n) for (ll UNUSED_NUMBER = 0; UNUSED_NUMBER < (n); ++UNUSED_NUMBER)
#define rep2(i, n) for (ll i = 0; i < (n); ++i)
#define rep3(i, a, b) for (ll i = (a); i < (b); ++i)
#define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
#define rrep1(n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep2(i,n) for(ll i = (n) - 1;i >= 0;i--)
#define rrep3(i,a,b) for(ll i = (b) - 1;i >= (a);i--)
#define rrep4(i,a,b,c) for(ll i = (a) + ((b)-(a)-1) / (c) * (c);i >= (a);i -= c)
#define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__)
#define all1(i) begin(i) , end(i)
#define all2(i,a) begin(i) , begin(i) + a
#define all3(i,a,b) begin(i) + a , begin(i) + b
#define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__)
#define sum(...) accumulate(all(__VA_ARGS__),0LL)
template<class T> bool chmin(T &a, const T &b){ if(a > b){ a = b; return 1; } else return 0; }
template<class T> bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } else return 0; }
template<class T> auto min(const T& a){return *min_element(all(a));}
template<class T> auto max(const T& a){return *max_element(all(a));}
template<class... Ts> void in(Ts&... t);
#define INT(...) int __VA_ARGS__; in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__; in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__; in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__; in(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__; in(__VA_ARGS__)
#define VEC(type, name, size) vector<type> name(size); in(name)
#define VV(type, name, h, w) vector<vector<type>> name(h, vector<type>(w)); in(name)
ll intpow(ll a, ll b){ ll ans = 1; while(b){if(b & 1) ans *= a; a *= a; b /= 2;} return ans;}
ll modpow(ll a, ll b, ll p){ ll ans = 1; a %= p;if(a < 0) a += p;while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
ll GCD(ll a,ll b) { if(a == 0 || b == 0) return 0; if(a % b == 0) return b; else return GCD(b,a%b);}
ll LCM(ll a,ll b) { if(a == 0) return b; if(b == 0) return a;return a / GCD(a,b) * b;}
namespace IO{
#define VOID(a) decltype(void(a))
struct setting{ setting(){cin.tie(nullptr); ios::sync_with_stdio(false);fixed(cout); cout.precision(12);}} setting;
template<int I> struct P : P<I-1>{};
template<> struct P<0>{};
template<class T> void i(T& t){ i(t, P<3>{}); }
void i(vector<bool>::reference t, P<3>){ int a; i(a); t = a; }
template<class T> auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; }
template<class T> auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); }
template<class T, size_t... idx> void ituple(T& t, index_sequence<idx...>){
    in(get<idx>(t)...);}
template<class T> auto i(T& t, P<0>) -> VOID(tuple_size<T>{}){
    ituple(t, make_index_sequence<tuple_size<T>::value>{});}
#undef VOID
}
#define unpack(a) (void)initializer_list<int>{(a, 0)...}
template<class... Ts> void in(Ts&... t){ unpack(IO :: i(t)); }
#undef unpack
static const double PI = 3.1415926535897932;
template <class F> struct REC {
    F f;
    REC(F &&f_) : f(forward<F>(f_)) {}
    template <class... Args> auto operator()(Args &&...args) const { return f(*this, forward<Args>(args)...); }};
//constexpr int mod = 1000000007;
constexpr int mod = 998244353;
#line 2 "library/graph/graph-template.hpp"
template <typename T> 
struct Edge {
	int from, to;
	T cost;
	Edge() = default;
	Edge(int _to, T _cost) : from(-1), to(_to), cost(_cost) {}
	Edge(int _from, int _to, T _cost) : from(_from), to(_to), cost(_cost) {}
	bool operator < (const Edge &a) const { return cost < a.cost; }
	bool operator > (const Edge &a) const { return cost > a.cost; }
    Edge &operator = (const int &x) {
        to = x;
        return *this;
    }
    operator int() const { return to; }
    friend ostream operator<<(ostream &os, Edge &edge) { return os << edge.to; }
};
 
template <typename T>
using Edges = vector<Edge<T>>;
template <typename T>
using Wgraph = vector<Edges<T>>;
using Ugraph = vector<vector<int>>;
Ugraph uinput(int N, int M = -1, bool is_directed = false, int origin = 1) {
    Ugraph g(N);
    if (M == -1) M = N - 1;
    while(M--) {
        int a,b;
        cin >> a >> b;
        a -= origin, b -= origin;
        g[a].push_back(b);
        if(!is_directed) g[b].push_back(a);
    }
    return g;
}
template <typename T>
Wgraph<T> winput(int N, int M = -1, bool is_directed = false,int origin = 1) {
    Wgraph<T> g(N);
    if (M == -1) M = N - 1;
    while(M--) {
        int a,b;
        T c;
        cin >> a >> b >> c;
        a -= origin, b -= origin;
        g[a].emplace_back(b,c);
        if(!is_directed) g[b].emplace_back(a,c);
    }
    return g;
}
#line 3 "library/tree/tree-query.hpp"
template <typename G>
struct Tree {
    private:
    G &g;
    //G g;
    int root;
    vector<vector<int>> bl;
    vector<int> dp;
    void build() {
        bl.resize(g.size());
        dp.resize(g.size());
        dfs(root, -1, 0);
    }

    void dfs(int c,int p, int dis) {
        dp[c] = dis;
        for(int i = p,x = -1;i != -1;) {
            bl[c].push_back(i);
            i = ++x < (int)bl[i].size() ? bl[i][x] : -1;
        }
        for (int d :g[c]) {
            if(d == p)continue;
            dfs(d,c,dis + 1);
        }
    }
    public:
    //Tree(): root(0){}
    Tree(G &_g,int _root = 0):g(_g),root(_root) {build();}

    int depth(int u) const{ return dp[u]; }

    int parent(int u) const{ return u == root ? -1: bl[u][0];}

    int kth_ancestor(int u, int k) const {
        if (dp[u] < k) return -1;
        for(int i = k ? __lg(k):-1; i >= 0; --i) {
            if ((k >> i) & 1) u = bl[u][i];
        }
        return u;
    }

    int next(int st,int gl) const {
        if(dp[st] >= dp[gl]) return parent(st);
        int u = kth_ancestor(gl,dp[gl] - dp[st] - 1);
        return bl[u][0] == st ? u:bl[st][0];
    }

    vector<int> path(int st,int gl) const {
        vector<int> pre,suf;
        while(dp[st] > dp[gl]) {
            pre.push_back(st);
            st = bl[st][0];
        }
        while (dp[st] < dp[gl]) {
            suf.push_back(gl);
            gl = bl[gl][0];
        }
        while (st != gl) {
            pre.push_back(st);
            suf.push_back(gl);
            st = bl[st][0];
            gl = bl[gl][0];
        }
        pre.push_back(st);
        reverse(begin(suf),end(suf));
        copy(begin(suf),end(suf),back_inserter(pre));
        return pre;
    }

    int lca(int u,int v) {
        if (dp[u] != dp[v]) {
            if (dp[u] > dp[v]) swap(u,v);
            v = kth_ancestor(v,dp[v] - dp[u]);
        }
        if (u == v)return u;
        for(int i = __lg(dp[u]);i >= 0;--i) {
            if (dp[u] < (1 << i)) continue;
            if (bl[u][i] != bl[v][i]) u = bl[u][i],v = bl[v][i];
        }
        return bl[u][0];
    }

    int distance(int u,int v) {
        int ancestor = lca(u,v);
        return dp[u] + dp[v] - 2 * dp[ancestor];
    }
};
#line 86 "main.cpp"
int main() {
    INT(n,q);
    vvi g(n);
    rep(i,n-1) {
        INT(a,b);
        a--,b--;
        g[a].emplace_back(b);
        g[b].emplace_back(a);
    }
    Tree<vvi> tree(g);
    vi ch(n);
    auto dfs = REC([&](auto &&f,int now,int par) -> void {
        for(auto &nex:g[now]) {
            if(nex != par) {
                f(nex,now);
                ch[now] += ch[nex]; 
            }
        }
        ch[now]++;
    });
    dfs(0,-1);
    debug(ch);
    rep(i,q) {
        INT(s,t);
        debug(s,t);
        s--,t--;
        int d = tree.distance(s,t);
        debug(d);
        if(d % 2) {
            cout << 0 << '\n';
            continue;
        }
        int ans = 0;
        if(tree.depth(s) == tree.depth(t)) {
            int lca = tree.lca(s,t);
            ans = n - ch[tree.next(lca,s)] - ch[tree.next(lca,t)];
        }
        else {
            if(tree.depth(s) < tree.depth(t)) swap(s,t);
            int mid = tree.kth_ancestor(s,d / 2);
            debug(mid);
            ans = ch[mid] - ch[tree.next(mid,s)];
        }
        cout << ans << '\n';
    }
}
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